JPH0686885U - Backing ring for steel pipe anti-relay welding - Google Patents

Abstract

(57) [Summary] [Purpose] In relay welding of steel pipe piles, to prevent welding failure due to unmelted residue, burned-out metal, and squeeze out of molten metal. Perform quality inspection accurately. [Structure] A plurality of thin rods 12 are radially attached to a ring body 11 inserted into the welded ends of the lower pile and the upper pile. A ring body 1 is provided with a notch at the base of the thin rod 12.
The thin rod 12 can be easily separated from 1.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a backing ring that is inserted into a welding end portion across a lower pile and an upper pile when relay welding a steel pipe pile and forms a groove between the end faces.

[0002]

[Prior art]

 In relay welding of steel pipe piles, a backing ring is used to form a groove between the end faces of the weld end. As this backing ring, JP-A-61-232062 and Japanese Utility Model Laid-Open No. 64-20996 disclose a functional backing ring having a plurality of holding pieces formed by punching. The structure and usage of this backing ring are shown in FIGS.

The backing ring 40 has holding pieces 41 at a plurality of positions (for example, four positions) in the circumferential direction of an intermediate portion in the axial direction. The holding piece 41 is formed by punching a part of the backing ring 40 and bending it outward.

As a usage method, first, the lower half portion of the backing ring 40 is inserted into the upper end portion of the lower pile 20. Since the retaining piece 41 engages with the upper end surface of the lower pile 20, the backing ring 40 is self-supported. Next, the upper pile 30 is butted to the lower pile 20. As a result, the upper half of the backing ring 40 is inserted into the lower end of the upper pile 30. Further, since the holding piece 41 is interposed between the end surfaces of the lower pile 20 and the upper pile 30, a predetermined route interval is secured between them.

That is, since the backing ring 40 has the holding piece 41, the backing ring 40 has a self-holding function and a function of ensuring a root interval.

When the lower pile 20 and the upper pile 30 are butted, circumferential welding is performed on the groove formed between the end faces thereof. At this time, the backing ring 40 forms the bottom surface of the groove and holds the molten metal in the groove to improve the welding quality.

[0007]

[Problems to be solved by the device]

 However, while such a backing ring is functional, the length of the holding piece cannot be extremely shortened in order to ensure that function. Further, as will be described later, it is necessary to lengthen the holding piece to some extent because there is a gap between the inner surface of the pile and the inner surface of the ring. Therefore, the holding piece may not be completely melted during welding.

Therefore, it seems that the holding piece is removed by a grinder or a gouging after performing the tack welding, but the work is troublesome and the workability is significantly reduced.

As shown in FIG. 2, since the holding piece 41 is bent, an R portion is formed on the holding piece 41. Therefore, a gap G is formed between the inner surface of the pile and the outer surface of the ring. Further, an opening 42 is formed in the backing ring as the holding piece 41 is bent. For these reasons, during main welding (first layer welding), weld failure is likely to occur due to the burn-through 43 and the protrusion 44 of the molten metal.

After welding, X-ray transmission imaging and ultrasonic flaw detection are performed to confirm the quality of the welded portion. However, the opening 42 formed due to the formation of the holding piece 41 interferes with the inspection, and melts. There is also the problem of making the contact quality inspection inaccurate.

The object of the present invention is to have not only a self-holding function and a route interval securing function, but also to prevent unmelted residue, burned-out, welding failure due to squeeze-out of molten metal, and further good workability. The purpose is to provide a backing ring that does not adversely affect quality inspection.

[0012]

[Means for Solving the Problems]

 The backing ring of the present invention is a backing ring that is inserted into the welded end across the lower pile and the upper pile when relay welding the lower pile and the upper pile made of steel pipe to form a groove between the end faces. And a cylindrical ring body in which the lower part and the upper part are inserted into the welded ends of the lower pile and the upper pile, respectively. The plurality of thin rods are provided so as to radially project from the position and to be separated from the ring body by an impact such as a hammer striking, and each of which has a notch at a base end thereof.

[0013]

[Action]

 In the backing ring of the present invention, a plurality of thin rods radially protruding from the ring body engage with the upper end surface of the lower pile and are interposed between the end surfaces of the lower pile and the upper pile. , Self-holding function and function to secure route interval can be obtained.

Since the thin rod is configured by attaching a member different from the ring body to the ring body without punching, the R portion does not occur at the base portion, and the inner surface of the ring body can be closely attached to the inner surface of the pile. . In addition, the opening due to punching can be eliminated from the ring body. Therefore, welding defects due to burn-through and exudation of molten metal can be prevented, and the welding quality can be inspected accurately.

Since the thin rod can be separated from the ring body, it can be lengthened, and a reliable self-holding function and a route interval ensuring function can be obtained. In addition, this separation eliminates the unmelted residue, and the separation work is easy and the workability is improved.

[0016]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. FIG. 3 is a perspective view showing an example of a backing ring of the present invention, FIG. 4 is an enlarged perspective view showing a thin rod portion, FIG. 5 is a cross-sectional view illustrating a thin rod mounting structure, and FIG. 6 is a backing ring. It is a perspective view for explaining the usage of a ring.

The main backing ring 10 is composed of a cylindrical ring body 11 and a plurality of thin rods 12 radially protruding outward from a plurality of positions in the circumferential direction of the central portion in the axial direction.

The ring body 11 is made of steel, and has a slit 11a formed obliquely from the upper end surface to the lower end surface. Due to the slit 11a, the ring body 11 can be expanded in diameter in accordance with the inner diameter of the steel pipe pile. A metal fitting 11b is attached to the inner surface of the ring body 11a to fix the ring body 11 in the expanded state. The metal fitting 11b is provided so as to straddle the slit 11a, and is welded to one inner surface sandwiching the slit 11a. The upper end of the ring body 11 is gradually reduced in diameter toward the upper end to facilitate insertion into the steel pipe pile.

The thin rods 12 are round rods made of steel, and are arranged at intervals of 60 degrees in the circumferential direction of the ring body 11. The thin rod 12 is attached to the ring main body 11 in a mode shown in FIGS. 5 (A) and 5 (B), for example. In FIG. 5 (A), the base end surface of the thin rod 12 is stud welded (arc pressure welded) to the outer surface of the ring body 11. In FIG. 5 (B), the base end portion of the thin rod 12 is a male screw. It is screwed into a screw hole provided in the ring body 11, and the screwed portion is welded from the inner surface side of the ring body 11.

As shown in FIG. 4, a notch 12 a opened upward is provided at the base of the thin rod 12 close to the outer surface of the ring body 11. The depth of the cut 12a is determined so that when the thin rod 12 is hit with a hammer, the thin rod 12 is easily broken at the cut 12a. The distance from the outer surface of the ring body 11 to the notch 12a is preferably as small as possible in order to reduce the trace after the thin rod 12 is removed.

The diameter of the thin rods 12 is equal to the desired root interval, and the length thereof is sufficiently thicker than the wall thickness of the steel pipe pile to be welded (for example, wall thickness + about 20 mm).

Next, a method of using the backing ring 10 will be described.

As shown in FIG. 6A, the ring body 11 is inserted into the upper end portion of the lower pile 20 until the thin rod 12 of the backing ring 10 contacts the upper end surface of the lower pile 20. When the thin rod 12 hits the upper end surface of the lower pile 20, the backing ring 10 is self-held with its upper portion protruding above the upper pile 20.

The ring body 11 is expanded in diameter until the outer surface of the ring body 11 comes into close contact with the inner surface of the lower pile 20. In this state, the open side of the metal fitting 11b is welded to the inner surface of the ring body 11. As a result, the ring body 11 is fixed such that its outer surface is in close contact with the inner surface of the lower pile 20.

As shown in FIG. 6B, the upper pile 30 is butted against the lower pile 20. At this time, since the round bar 12 is interposed between the end faces of the upper piles of the lower piles 20, a desired route interval can be secured between them. The round bar 12 projects outside the groove formed between the lower pile 20 and the upper pile 30. Further, the bottom of the groove is closed by the ring body 11.

The lower pile 20 and the upper pile 30 are tack welded at a plurality of circumferential positions of the groove. 50 is the weld.

After welding, as shown in FIG. 6C, the thin rod 12 is separated from the ring body 11 by hitting the thin rod 12 with a hammer and breaking the thin rod 12 at the notch 12a. Then, main welding is performed on the groove.

If the backing ring 10 is used, not only the self-holding function and the root interval maintaining function are obtained, but also the thin rod 12 for obtaining those functions is used as a member different from the ring main body 11 to form a ring. Since it is attached to the main body 11, the R portion is not formed on the base of the thin rod 12, and the outer surface of the ring main body 11 can be surely brought into close contact with the inner surface of the pile.

Further, the opening due to punching is eliminated from the ring body 11. Therefore, it is possible to prevent welding failure due to burn-through and molten metal protrusion in the main welding.

In addition, since the thin rod 12 is separated from the ring body 11 during the main welding, and traces 12b thereof are slightly left on the ring body 11, the thin rod 12 does not remain unmelted and welding is also performed from this surface. Quality is improved.

Since the thin rod 12 is long, a reliable self-holding function and a function for ensuring the root interval can be obtained, and even if the thin rod 12 is lengthened, it is removed, so that unmelted residue does not occur.

Further, the removal of the thin rod 12 is easily performed by hitting with a hammer or the like, and the removal of the thin rod 12 does not lead to a decrease in workability.

When X-ray radiography or ultrasonic flaw detection is performed to confirm the quality of the welded portion after welding, the quality inspection is accurate because there is no punched opening in the ring body 11. To be done.

[0034]

[Effect of device]

 As explained above, the backing ring of the present invention is equipped with a thin rod that can be easily removed on the ring body in order to obtain the self-holding function and the root interval maintaining function, so that the unmelted residue, the burned-out metal, and the molten metal Welding defects caused by protrusion can be prevented. Despite the removal of the thin rod, this removal process does not take much effort and the workability is good. There is no risk of adversely affecting quality inspection.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a structure of a conventional backing ring.

FIG. 2 is a cross-sectional view for explaining problems with a conventional backing ring.

FIG. 3 is a perspective view showing an example of a backing ring of the present invention.

FIG. 4 is an enlarged perspective view showing a thin rod portion.

FIG. 5 is a cross-sectional view illustrating a mounting structure of a thin rod.

FIG. 6 is a perspective view for explaining how to use the backing ring.

[Explanation of symbols]

 10 Backing Ring 11 Ring Body 12 Thin Rod 12a Notch 20 Lower Pile 30 Upper Pile

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Hiromitsu Fujikawa, 1850 Minato Minato, Wakayama, Wakayama Sumitomo Metal Industries, Ltd. Wakayama Works (72) Mikio Komai, 18th Tsukikohamaji Nishimachi, Sakai City, Osaka Prefecture High Voltage Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. When relay-welding a lower pile and an upper pile made of steel pipe, the lower pile and the upper pile are inserted into the welding end portion over the lower pile and the upper pile,
A backing ring that forms a groove between the end faces, and a cylindrical ring body in which the lower part and the upper part are respectively inserted into the welding ends of the lower pile and the upper pile, and the ring body attached to the ring body. Along the radial center of the axial center, the plurality of thin grooves are provided at each base end so that they can be separated from the ring body by the impact of hammer impact. A backing ring for steel pipe anti-relay welding, comprising a rod.